Wrench



Sept 28, A1943. A. BoYNToN 2,330,201r

' WRENCH Filed April a, 1959 A ron/v5 r's.

Patented Sept. 28, 1943 plv-iran WRENCH Alexander Boynton, Sany Antonio, Tex,` v Y Application April s, 1939, semaine; 266,759 l J3 Claires; (MA311-179)"A My invention relates to'wrenches, particularly,1 to pipe wrenches.` y Theobjects are to provide a tia'lly complete circumferential surface of rthe pipe, (4) will grip the pipe with uniformlynincreasing force` as increasing force is `applied to operate it, and (5) willl automatically return the pipe gripping dogs to their starting position each time the wrench is removed from the pipe.;

I attain the foregoing objects by means of two shellsor jaws, each preferably containing'a plu.- rality of pipe gripper dogs, one shell or jaw-being pivoted orvhinged to the lwrench handle and theother shell or jaw -being hinged to the other shell yor jaw, an arm and roller` upon the handle being adaptedto urge the dogs together upon the pipe, aswill more clearly appear from the accom-A panying ydrawing in which:

Fig. lis atop View of ,the preferred embodiment-f. ,f Y

Fig. 2 is a sectional view taken on the line A2,---2,

Fig. 3. 1 Fig. 3 is a side View of the assembly showniin Fig. 1. f L Fig. 4 is a section on the line 4 4, Fig.1.

Fig. 5,is (a perspective view of one of thejpipe gripper dogs.- t t j Fig. 6 is a section on the line I,-B, Fig. vl.

Similar characters refer to similar jparts throughout the several views. i

Referringto` Figs. 1 `to 6, bothzinolusive:'the` handle member I ishingeduponjdouble hinged,

shell or jaw 2 by hinge bolt 3 and the single hinged shell or jaw 31is hinged upon jaw 2 by bolt I0. Each of the eccentric pipe gripper dogs 1 has a rib 1b (see Fig. 5) adapted to be received within the spring cases 5 to each of which cases each dog is secured by a pin 4 which passes through the opening 1c of the ribs 1b, said pin having split end 4a bent over to secure the assembly. as appears in Fig. 4. The spring cases 5 and 5a, are closely received within the openings between the upper and lower ribs of jaws 2 and 3 where they are also secured by pins 4 passing through slots in these cases similar to the slots 3b in the jaws, the heads and split ends 4a being received within slots 3b. Each of the spring base lugs 6, slidable within spring cases 5 and 5a, has a pin 5a. closely engaged within an opening in dogs l, and each of the springs 8 has one end landed upon one of these lugs and the other end landed upon one of the pillars 2a, as appears in Fig. 2. The slots 3b extending through the spring cases wrench that 1 (l) will not mashthe pipe, (2) will not deeply score theY pipe, (3)y will `closeevenly ruponl asubStan- 5 and 5a.v provide that thesecases` may have lirnited circular movement within the opening ,bef v-tweenjthe upper and lower semi-circular rib-like portions of jaws 2 and 3. The springs are normally-'held somewhat compressed against pillars 2a bylugs lil (seeoFig. 2). `These springs, of course, are so made as to be compressible somewhatbeyond the necessarytravelof4 the pipe grippers. b 1 v In operation, the clearance between the bumper I b andthev Asurface, 2c will allow the roller l2,v to clearA rib 5b and thestop bumper 3a `will land upon the surface v2b after the single hinged jaw 3 hasfbeen opened topadmitpipev I3, as in Fig-:1.

The operator is assumedtojbe positioned ontheV front side `of the wrench, that `side being theside wherejth'e roller wheel I2 is mounted withinxthe;

forkedendVof'ar-m.Iaupon axle bolt Il. `rIfhe handlegis then moved clockwise toward the oper-f ator. This movement causes the roller` I2 to engagejupon.the-rib4 5b, asappearsin Figs. 1, 2,and 3, The handle'beingpulled further causes the pipe gripper dog teeth 'la tobeurged .upon the pipe I3, because the dogs areeccentric rwithref-` erenceito the pipe and are-forced inwardly yby the resulting clockwise movementyof the eccentric surfaces of thejaws 2 and 3 contacting Vrand'mcvfv ing uponthe mating eccentric surfaces of, the

dogs 1. The'angle between arm la and a line tangent to rib 5b at vthe point where the roller wheel I2 first contacts this rib when thehandle member I is pulled'forward is such that the roller wheelpwillv urge the pipe gripper dogs together, as is apparent in Figs. 1 andV 2.V By an anticlockwise thrust of the handle with one hand, while'the other hand'is yemployed to open the; shell 3, it is apparent that the wrench may be readilyv removed from the pipe by reversing the described movement required to apply it to the pipe, as is apparent in Fig. 1.

The eccentric relation between the dogs 1 and .cases 5 and 5a are the same throughout, and the throw of the eccentrics are sufficient for the dogs to iit loosely 'over the pipe in one position and to close together upon it in the other position. It is therefore apparent that the dogs will move evenly toward or away from the pipe and will fasten upon it or release it as the handle is moved clockwise or anti-clockwise, respectively.

It will be observed that the dogs 1 and one end of springs 8 landed upon the lugs 6 become stationary with reference to the pipe I3 as soon as thewrench is applied thereon andthat the subsequent clockwise movement of the handle will compress springs 8 by the movement of pillars 2a because both jaws 2 and 3 and spring cases 5 and 5a move clockwise with the handle to which the shells are secured by hinge bolts 9 and Ill. Each time the pipe is released the springs return the pipe gripper dogs 'to their normal positions, as in Figs. 1 and 2.

It is obvious that mechanical changes, substitutions and adaptations may be made in the structure, and that equivalents may be substituted for the parts shown; and I reserve the right to make such mechanical changes, substitutions, and adaptations within the scope of the invention as comprehended by the stated objects and appended claims.

What is claimed is:

1. In a pipe wrench a pair of jaws adapted to surround a pipe, gripping dogs within said jaws, said dogs having outwardly facing eccentric surfaces and a fin of rectangular cross section therebetween, an outwardly extending lug on each of said dogs, a stop on each of the jaws in spaced relation with said lug, a coil spring interposed between each lug and associated stop, and an arcuate spring case surrounding said spring, said spring case having a slot adapted to receive said lug, and means slidably securing a spring case to each of said dogs with the ends of the enclosed spring in engagement with one cf the stops and the lug respectively.

2. In a pipe wrench, a. pair of clamp jaws adapted to surround a pipe, means for pivoting said jaws together at one end of the jaws, a handle member pivoted to one of said jaws at the other end of said one jaw, an arm member on said handle member for engaging and forcing inwardly the other of said clamp jaws on movement of said handle member in a pipe engaging direction, a plurality of gripper dogs slid.- ably engaging said jaws, said gripper dogs having dog teeth adapted to engage the pipe surface, a cam surface on each of said gripper dogs, an oppositely disposed cam surface on each of said-clamp jaws adapted to cooperate with the adjacent cam surface of each of the gripper dogs to urge the dog teeth into engagement with the pipe surface on 'movement of said handle member in a pipe engaging direction, a spring member for each of said gripper dogs, a casing secured to each of said gripper dogs, and adapted to receive and mount said spring member, a dog stop member mounted on each of said gripper dogs, a clamp jaw stop member spaced circum` ferentially from said dog stop member and mounted on each of said jaws so as to move therewith, said casing operating to hold said spring member under initial compression between said dog stop member and said clamp jaw stop member with its ends in abutment therewith so as to amplify said initial compression of said spring on directional movement of said handle 5 member for gripping engagement of the dog teeth with the pipe and to urge the gripper dogs into their released original positions relative to said clamp jaws on releasing movement of said handle member.

3. In a pipe wrench, a pair of clamp jaws hinged at one end thereof, said jaws being forked at portions thereof to provide openings to receive spring housings therein, and curved in contour to permit surrounding a pipe, a bell crank lever l5 pivoted to one of said clamp jaws at the other end of said one clamp jaw, said bell crank lever having a handle member and an arm member extending outwardly from said pivot, a roller carried at the outer end of the arm member adapted to engage the other of said clamp jaws on movement of said handle member in a pipe engaging direction, a plurality of gripper dogs having teeth adapted to engage a pipe surface,

a central rib portion and a stop member on each of said gripper dogs, and lateral cam surfaces on each side of said rib portion, an opening extending transversely through said rib portion, a

spring housing extending over the said central rib portions and into said openings between the forked portions of the said jaws, longitudinal slot members in the side portions of said housings and the forked portions of the said jaws, holding members extending through the transverse opening in said rib portion and through the longitudinal slot members of the housing to hold the housing in place and to permit relative longitudinal movement between said gripper dogs and said clamp jaws together with said spring housings, a spring member mounted in each of 4o said housings, a jaw stop member connected to each of said jaws so as to engage each spring member and to hold the same in compression between a dog stop member and a jaw stop member, cam surfaces on said jaw members disposed laterally thereon so to engage the corresponding lateral cam surfaces on the said gripper dogs in opposed relation so that by relative movement of the gripper dogs and the clamp jaws along the said cam surfaces, the pressure of the dog teeth against the pipe surface is increased and by relative movement in the opposite ldirection the pressure is decreased and bumper stop members to limit the relative movement of the jaw members and the said handle member.

ALEXANDER BOYNTON. 

